MaterialsgateNEWS
2017/02/15

Related MaterialsgateCARDS

New method to detect ultrasound with light

A tiny, transparent device that can fit into a contact lens has a bright future, potentially helping a range of scientific endeavors from biomedicine to geology.

Developed by Northwestern University scientists, the device, called the Micro-ring resonator detector, can determine the speed of the blood flow and the oxygen metabolic rate at the back of the eye. This information could help diagnose such common and debilitating diseases as macular degeneration and diabetes.

The Micro-ring device builds upon Professor Hao F. Zhang's groundbreaking work in 2006 to develop photoacoustic imaging, which combines sound and light waves to create images of biological materials. The imaging technique is being widely explored for both fundamental biological investigations and clinical diagnosis, from nanoscopic cellular imaging to human breast cancer screening.

For three years, Zhang, associate professor of biomedical engineering, worked with Cheng Sun, associate professor of mechanical engineering, and their post-doctoral fellows Biqin Dong and Hao Li to create the Micro-ring resonator detector.

"We believe that with this technology, optical ultrasound detection methods will play an increasingly important role in photoacoustic imaging for the retina and many biomedical applications," Zhang said.

The team's work on the device resulted in a review article, published in the January 2017 edition of the journal Transactions on Biomedical Engineering.

In 2006, Zhang was exploring new retinal imaging technologies when Dr. Amani Fawzi, now an associate professor of ophthalmology at Northwestern's Feinberg School of Medicine, approached him to create a new diagnostic device that could measure biological activities at the back of the eye.

"We needed a device that had large enough bandwidth for spatial resolution," Zhang said. "And it needed to be optically transparent to allow light to go through freely."

"Ultrasound detection devices of that time were usually bulky, opaque, and not sensitive enough. And they had limited bandwidth," Sun said. "It could only capture part of it what was happening in the eye."

To meet Fawzi's challenge, the team needed to develop a radically different type of detector -- small enough to be used with human eyes, soft enough to be integrated into a contact lens and yet generate a super-high resolution of hundreds of megahertz.

"The trouble was to fabricate it, have it fit in the size of a contact lens, and make it still work," Sun said.

First, the team considered a device that placed the needle-sized detector on the eyelid, but that method was not ideal. Next, they landed on the idea of a tiny ring implanted in a single-use contact lens worn during diagnosis.

However, that idea added an extra challenge -- making the device transparent.

After nearly three years of work, they created the plastic Micro-ring resonator, a transparent device that is 60 micrometers in diameter and 1 micron high. There is movement toward using it with patients.

The team continues to improve the device with support from Northwestern, the National Institutes of Health, Argonne National Laboratory, and the National Science Foundation.

As word spreads about the device, about a dozen scientists from a variety of fields have approached the team about adapting it for their own work. For instance:

- Urologists want to use the system to study the optics of breast cancer cells, information that could lead to new treatments.

- Neuroscientists are interested in using the Micro-ring resonator as a window into rodent brains as a way of studying drug protection for the cortex during different points of a stroke. "Typically, researchers use a pure piece of glass, but this allows for a lot more types of imaging," Zhang said.

- Geologists aim to use the technology to investigate the earth crust and earthquake. "Hearing from a geologist--that was a surprise," he added.

Source: Northwestern University – 13.02.2017.

Investigated and edited by:

The investigation and editing of this document was performed with best care and attention.
For the accuracy, validity, availability and applicability of the given information, we take no liability.
Please discuss the suitability concerning your specific application with the experts of the named company or organization.

You want additional material or technology investigations concerning this subject?

More on this topic

New technique to 'freeze' newly created microbubbles in their tracks could lead to new applications in medicine and the nuclear industry

Controlling bubbles is a difficult process and one that many of us experienced in a simplistic form as young children wielding a bubble wand, trying to create bigger bubbles without popping them. A research team in CINaM-CNRS Aix-Marseille Université in France has turned child's play into serious business.
They demonstrated they could immobilize a microbubble created from water electrolysis as if the Archimedes' buoyant force that would normally push it to the surface didn't exist. This new and surprising phenomenon described this week in Applied Physics Letters, from AIP Publishing, could lead to applications in medicine, the nuclear industry or micromanipulation technology... more

Robotically steering flexible needles can reach their intended target in tissue with sub-millimetre level accuracy. This has been demonstrated by the doctoral research of Momen Abayazid, who is affiliated with the research institute MIRA of the University of Twente.

An major advantage of steering flexible needles is that one can avoid obstacles or sensitive tissues and can re-orient the path of the needle in real time as you insert the needle. Abayazid will defend his doctoral thesis on 26 August, 2015.
During many diagnostic and therapeutic procedures a needle is inserted into soft tissue, such as during biopsies, or inserting radioactive seeds in order to combat prostate cancer. In many of these operations the accurate positioning of the needle is of the utmost importance. In general, rigid needles with a relatively large diameter are used in these procedures. However, the drawback of these needles is that they cannot be maneuvered when inserted into... more

Having proved that ultrasound degassing of molten aluminium alloys is cleaner, greener and cheaper than current methods, a team of scientists from Brunel University London working within a European consortium has now taken the breakthrough a step further.
De-gassing the melts of aluminium alloys is a vital process otherwise the resulting solid metals end up being highly porous and often rejected for further use.
Project lead Prof Dmitry Eskin of the Brunel Centre for Advanced Solidification Technology explains: "The most common current method, argon rotary degassing, is energy intensive, involves rotating brittle parts and expensive argon gas.
"Having proved that ultrasound... more

Researchers from North Carolina State University have developed a technique that allows ultrasound to penetrate bone or metal, using customized structures that offset the distortion usually caused by these so-called “aberrating layers.”

“We’ve designed complementary metamaterials that will make it easier for medical professionals to use ultrasound for diagnostic or therapeutic applications, such as monitoring blood flow in the brain or to treat brain tumors,” says Tarry Chen Shen, a Ph.D. student at NC State and lead author of a paper on the work. “This has been difficult in the past because the skull distorts the ultrasound’s acoustic field.”
“These metamaterials could also be used in industrial settings,” says Dr. Yun Jing, an assistant professor of mechanical and aerospace engineering at NC State and senior author of the paper. “For example, it would allow you to use ultrasound to detect cracks in airplane... more